ArcLength

Syntax

prior to v3.2.0

For versions prior to v3.2.0, the syntax is as follows. Only one single DoF is permitted to be controlled. It is directly defined in the step command.

step ArcLength (1) (2) (3) (4)
# (1) int, unique step tag
# (2) int, reference node tag
# (3) int, reference dof tag
# (4) double, reference magnitude of applied load

v3.2.0 and later

For versions v3.2.0 and later, the syntax is as follows. The reference load is no longer defined in the step command. Instead, it is defined by the RefForce command.

step ArcLength (1)
# (1) int, unique step tag

Arc-length Control

The step size in an arc-length analysis is now the arc length. One can use the following to control stepping strategy.

set ini_step_size (1)
set min_step_size (1)
set max_step_size (1)
# (1) double, step size (arc length)

set fixed_step_size (1)
# (1) bool, flag to indicate if to fix the arc length

Remarks

1. A Ramm solver with default parameters is automatically enabled if no valid Ramm solver is defined. Not all storage schemes are supported, please check Ramm documentation.